Research of trace metals as markers of entry pathways in combined sewers

摘要

Combined sewers receive high toxic trace metal loads emitted by various sources, such as traffic,nindustry, urban heating and building materials. During heavy rain events, Combined SewernOverflows (CSO) can occur and, if so, are discharged directly into the aquatic system andntherefore could have an acute impact on receiving waters. In this study, the concentrations ofn18 metals have been measured in 89 samples drawn from the three pollutant Entry Pathways innCombined Sewers (EPCS): i) roof runoff, ii) street runoff, and iii) industrial and domestic effluentsnand also drawn from sewer deposits (SD). The aim of this research is to identify metallic markersnfor each EPCS; the data matrix was submitted to principal component analysis in order tondetermine metallic markers for the three EPCS and SD. This study highlights the fact that metallicncontent variability across samples from different EPCS and SD exceeds the spatio-temporalnvariability of samples from the same EPCS. In the catchment studied here, the most valuable EPCSnand SD markers are lead, sodium, boron, antimony and zinc; these markers could be used innfuture studies to identify the contributions of each EPCS to CSO metallic loads.